An object of the present invention is to provide a separation method of zirconium and hafnium, which is more eco-friendly than the traditional solvent extraction methods thereof because no toxic chemical such as cyan is used, is economically advantageous because it is possible to extract hafnium contained in much less amount than zirconium selectively, so as to save great amount of extractant required for extraction and separation of metal. Since this method can reduce the content of hafnium in zirconium to below 50 ppm, maintaining over 95% of recovery rate of the zirconium, it is possible to increase separation effect of two metals dramatically in comparison with the traditional methods.
In order to achieve the above object, a separation method of zirconium and hafnium according to an example of the present invention comprises mixing step to prepare a crude liquid for extraction by mixing a sulfuric acid solution containing zirconium and hafnium, a catalyst, and an acidic extractants; and first extraction step to form a first extract solution layer comprising the acidic extractant in which the hafnium has been extracted and a sulfuric acid solution layer separated from the first extract solution layer.
The acidic extractant may include any one selected from the group consisting of D2EHPA (Di-(2-ethylhexyl)phosphoric acid), PC88A (2-Ethylhexyl phosphonic acid mono-2-ethylhexyl ester), and a combination thereof.
The catalyst may include iodine.
The content of sulfuric acid in the sulfuric acid solution may be 2 to 10 mol/L.
The content of the catalyst may be 0.01 to 0.1 g/L on the basis of the sulfuric acid solution.
The acidic extractant may include diluent which may be organic solvent, and the first extract solution layer in the first extraction step may include the diluent.
The separation method of zirconium and hafnium may further comprise separation step and reverse extraction step after the first extraction step.
The separation step may be a process to separate the first extract solution layer and the sulfuric acid solution layer. The reverse extraction step may be a process to prepare a second extract solution by mixing and stirring the first extract solution and water for extracting zirconium from the first extract solution layer to water.
The iodine is derived from any one selected from a group consisting of potassium iodide (KI), sodium iodide, (NaI), ammonium iodide (NH4I), and combinations thereof.